Termination for semiconductor devices, for example trench type MOSgated devices such as MOSFETs, IGBTs and the like are well known. It is also known that a plurality of termination rings in the termination region of MOSgated devices may be fabricated using special mask steps in order to increase the voltage blocking capability thereof above, for example, 200V. However, it is well known that increasing the number of mask steps leads to the increase in the fabrication time and cost and wafer defects.
Thus, it is desirable to reduce the number of masking steps in the fabrication of MOSgated devices that include multiple trenches in the termination region thereof.
In accordance with the present invention, in order to reduce the number of masking steps, the process of copending application Ser. No. 11/504,740, filed Aug. 15, 2006, is adapted for the fabrication of trench type MOSgated semiconductor devices with plural concentric termination trenches.
Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.